1 /*
2 * Copyright (C) 2016 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * * Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in
12 * the documentation and/or other materials provided with the
13 * distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <unistd.h>
30
31 #include <errno.h>
32 #include <fcntl.h>
33 #include <string.h>
34
lockf64(int fd,int cmd,off64_t length)35 int lockf64(int fd, int cmd, off64_t length) {
36 // Translate POSIX lockf into fcntl.
37 struct flock64 fl;
38 memset(&fl, 0, sizeof(fl));
39 fl.l_whence = SEEK_CUR;
40 fl.l_start = 0;
41 fl.l_len = length;
42
43 if (cmd == F_ULOCK) {
44 fl.l_type = F_UNLCK;
45 cmd = F_SETLK64;
46 return fcntl(fd, F_SETLK64, &fl);
47 }
48
49 if (cmd == F_LOCK) {
50 fl.l_type = F_WRLCK;
51 return fcntl(fd, F_SETLKW64, &fl);
52 }
53
54 if (cmd == F_TLOCK) {
55 fl.l_type = F_WRLCK;
56 return fcntl(fd, F_SETLK64, &fl);
57 }
58
59 if (cmd == F_TEST) {
60 fl.l_type = F_RDLCK;
61 if (fcntl(fd, F_GETLK64, &fl) == -1) return -1;
62 if (fl.l_type == F_UNLCK || fl.l_pid == getpid()) return 0;
63 errno = EACCES;
64 return -1;
65 }
66
67 errno = EINVAL;
68 return -1;
69 }
70
lockf(int fd,int cmd,off_t length)71 int lockf(int fd, int cmd, off_t length) {
72 return lockf64(fd, cmd, length);
73 }
74